The secretive Foreign Intelligence Surveillance Court approved all 1,506 government requests to electronically monitor suspected “agents” of a foreign power or terrorists on U.S. soil last year, according to a Justice Department report released under the Freedom of Information Act.

The two-page report, which shows about a 13 percent increase in the number of applications for electronic surveillance between 2009 and 2010, was obtained by the Federation of American Scientists and published Friday.

“The FISC did not deny any applications in whole, or in part,” according to the April 19 report to Sen. Majority Leader Harry Reid (D-Nevada).

The 11-member court denied two of 1,329 applications for domestic-intelligence surveillance in 2009. The FBI is the primary agency making those requests.

Whether the FISA court, whose business is conducted behind closed doors, is rubber-stamping the requests is a matter of debate.

“That’s been a traditional concern that the court might have become a rubber stamp and that it’s approval is only a formality,” Steven Aftergood, the director of the Project on Government Secrecy for the Federation of American Scientists, said by telephone. “The government’s argument, and it’s also an argument that has been made occasionally by the judges, is in fact the Justice Department has grasped the court’s expectations so well that the only applications they submit to the court are ones that are likely to meet its approval.”

The court, set up in 1978, issues warrants for domestic surveillance that are unlike the warrants issued in criminal investigations. The secret court warrants, under the authority of the Foreign Intelligence Surveillance Act, grant the government broad authority to secretly monitor the electronic communications of persons in the United States, generally for intelligence purposes only.

The targets of a FISA warrant may never learn of the surveillance. Whereas subjects of non-FISA warrants may challenge the warrants and the evidence gathered if it is used in a criminal prosecution.

Aftergood notes that the figures, whether they amount to rubber-stamping or not, do not account for the warrantless monitoring program President George W. Bush adopted in the wake of the 2001 terror attacks. Under the Terror Surveillance Program, exposed in 2005 by The New York Times, the government conceded it was eavesdropping — without warrants — on the electronic communications of Americans if they were communicating with somebody overseas believed linked to terrorism.

The Justice Department report, meanwhile, said the FBI issued 24,287 “national security letter” requests last year on 14,212 people, “a substantial increase from the 2009 level of 14,788 NSL requests concerning 6,114 U.S. persons,” Aftergood wrote in a blog post. In 2008, there were 24,744 requests regarding 7,225 people.

National security letters are written demands from the FBI that compel internet service providers, credit companies, financial institutions and others to hand over confidential records about their customers, such as subscriber information, phone numbers and e-mail addresses, websites visited and more.

They do not require court approval, and the FBI need merely assert that the information is “relevant” to an investigation, and anyone who gets a national security letter is prohibited from even disclosing that they’ve received one.